Infoblox DNS Threat Index finds criminals are creating more ransomware-domains than ever, and predicts a continuing increase in attacks as more criminals rush to cash in.

Emboldened by the wave of successful ransomware attacks in early 2016, more cybercriminals are rushing to take advantage of this lucrative crime spree.

Networking company Infoblox’s quarterly threat index shows cybercriminals have been busy in the first quarter of 2016 creating new domains and subdomains and hijacking legitimate ones to build up their ransomware operations.

The number of domains serving up ransomware increased 35-fold in the first three months of 2016 compared to the end of 2015, according to the latest Infoblox DNS Threat Index. The index doesn’t measure actual attack volumes but observes malicious infrastructure — the domains used in individual campaigns. Criminals are constantly creating new domains and subdomains to stay ahead of blacklists and other security filters. The fact that the attack infrastructure for ransomware is growing is a good indicator that more cybercriminals are shifting their energies to these operations.

“There is an old adage that success begets success, and it seems to apply to malware as in any other corner of life,” Infoblox researchers wrote in the report.

The threat index hit an all-time high of 137 in the first quarter of 2016, compared to 128 in fourth quarter 2015. While there was a lot of activity creating infrastructure for all types of attacks, including malware, exploit kits, phishing, distributed denial-of-service, and data exfiltration, the explosion of ransomware-specific domains helped propel the overall threat index higher, Infoblox said in its report. Ransomware-related domains, which include those hosting the actual download and those that act as command-and-control servers for infected machines, accounted for 60 percent of the entire malware category.

“Again in simple terms: Ransomware is working,” the report said.

Instead of targeting consumers and small businesses in “small-dollar heists,” cybercriminals are shifting toward “industrial-scale, big-money” attacks on commercial entities, said Rod Rasmussen, vice president of cybersecurity at Infoblox. Cybercriminals don’t need to infect several victims for $500 each if a single hospital can net them $17,000 in bitcoin, for example.

The latest estimates from the FBI show ransomware cost victims $209 million in the first quarter of 2016, compared to $24 million for all of 2015. That doesn’t cover only the ransoms paid out — it also includes costs of downtime, the time required to clean off the infection, and resources spent recovering systems from backup.

Toward the end of 2015, Infoblox researchers observed that cybercriminals appeared to have abandoned the “plant/harvest cycle,” where they spent a few months building up the attack infrastructure, then a few months reaping the rewards before starting all over again. That seems to be the case in 2016, as there was no meaningful lull in newly created threats and new threats — such as ransomware — jumped to new highs. The harvest period seems to be less and less necessary, as criminals get more efficient shifting from task to task, from creating domains, hijacking legitimate domains, creating and distributing malware, stealing data, and generally causing harm to their victims.

“Unfortunately, these elevated threat levels are probably with us for the foreseeable future — it’s only the nature of the threat that will change from quarter to quarter,” Infoblox wrote.

Ransomware may be the fastest-growing segment of attacks, but it still accounts for a small piece of the overall attack infrastructure. Exploit kits remain the biggest threat, accounting for more than 50 percent of the overall index, with Angler leading the way. Angler is the toolkit commonly used in malvertising attacks, where malicious advertisements are injected into third-party advertising networks and victims are compromised by navigating to websites displaying those ads. Neutrino is also gaining popularity among cybercriminals. However, the lines are blurring as Neutrino is jumping into ransomware, as recent campaigns delivered ransomware, such as Locky, Teslacrypt, Cryptolocker2, and Kovter, to victims.

Recently, multiple reports have touted ransomware’s rapid growth, but what gets lost is that ransomware isn’t the most prevalent threat facing enterprises today. Organizations are more likely to see phishing attacks, exploit kits, and other types of malware, such as backdoors, Trojans, and keyloggers. Note Microsoft’s recent research, which noted that in 2015, ransomware accounted for less than 1 percent of malware. The encounter rate for ransomware jumped 50 percent over the second half of 2015, but that is going from 0.26 percent of attacks to 0.4 percent. Even if there are 35 times more attacks in 2016, that’s still a relatively small number compared to all other attacks.

The good news is that staying ahead of ransomware requires the same steps as basic malware prevention: tightening security measures, keeping software up-to-date, and maintaining clean backups.

“Unless and until companies figure out how to guard against ransomware — and certainly not reward the attack — we expect it to continue its successful run,” warned the report.